A Health Savings Account (HSA) and a Flexible Spending Account (FSA) both let you set aside pre-tax money for medical costs, but they work very differently on three points that matter most: who can open one, whether unused money rolls over, and whether the account is yours to keep. This is a side-by-side of how they differ — not advice on which to choose, since that depends on your health plan and situation.
IRS-governed — offered via banks, brokerages, and employers
Portable, investable, and rolls over forever — but requires an HSA-qualified high-deductible health plan.
Pros
IRS-governed — offered through your employer
Full annual election available on day one — but employer-owned and largely use-it-or-lose-it.
Pros
Pick Health Savings Account (HSA) if: People enrolled in (or able to choose) an HSA-qualified HDHP who want an account they keep for life and can invest.
Pick Flexible Spending Account (FSA) if: People whose health plan is not HDHP-qualified, or who want the full annual amount available immediately for predictable expenses.
Read IRS Publication 969 →Read IRS Publication 969 →
The biggest structural difference is portability and rollover. HSA funds are yours permanently — they roll over indefinitely, grow tax-free, and travel with you if you change jobs. FSA funds are employer-owned, don't roll over (except up to $640 in 2024 with an employer's grace plan), and are forfeited if you leave your job with a balance. HSAs also require enrollment in a High-Deductible Health Plan (HDHP); FSAs are available with most employer health plans. Source: IRS Publication 969 at irs.gov.
Generally no — if you have an HSA-eligible HDHP, you can only pair it with a Limited-Purpose FSA (restricted to dental and vision expenses), not a standard healthcare FSA. A dependent-care FSA is separate and can be paired with an HSA. Combining a general healthcare FSA with an HSA violates IRS rules and could result in loss of HSA tax advantages. Source: IRS Publication 969 at irs.gov.
For long-term savings, an HSA is structurally superior: triple tax advantage (pre-tax contributions, tax-free growth, tax-free withdrawals for qualified medical expenses), indefinite rollover, and the ability to invest the balance like a retirement account after age 65. An FSA is better if you don't have access to an HDHP, need predictable medical spending reimbursed immediately, or your employer contributes to an FSA. This is a structural comparison, not personalized tax advice — consult a qualified tax advisor for your situation. Source: IRS.gov.
FSA funds that aren't used by the plan year deadline are forfeited (the 'use it or lose it' rule). Some employers offer a grace period extension (up to 2.5 months) or allow a limited rollover ($640 in 2024, indexed to inflation), but neither is required by law. This is a key reason to estimate your medical spending carefully before electing FSA contributions. HSAs have no use-it-or-lose-it requirement. Source: IRS Publication 969 at irs.gov.
Independent editorial comparison. ClearValue Lending is not the issuer of any product compared here; affiliate links may pay a referral commission at no cost to you — selection is independent of compensation.